"Pfft, don't be stupid, how would that even work?" Marcia said, as her roommate Sally held up her phone, having made a rather astonishing claim

"Well, Marcia, it's all to do with low-frequency audio signals combined with research into the subconscious mind. I can't tell you everything...."

" Oh, 'cos the dumb track scholarship girl won't understand the big words?"

Sally sighed at the interruption, and put in her earbuds

"Ah, don't be like that, Sal, I'm just kidding, I know you have to keep the research secret until you guys are ready to publi-" Marcia said, cutting off as Sally pressed a button.

She stood there, paused in mid-sentence, as a faint hum could just be heard in the room, coming from the phone's speakers.

"...Apology accepted, Marcia, but I wasn't mad, I was about to do this anyway. And no point explaining now, you won't remember anything after this test. "

A few typed commands, and Marcia unlocked her phone, letting Sally add the app to transmit the signals through remote wifi control, turning Marcia's phone into a receiver for commands from Sally's own control app.

"Now... let's have you walk to the other side of campus to check this remote control function works, and we'll see what else comes to mind."

Marcia walked stiffly out of the room, Sally already plotting ways to maybe get her app onto some other phones around the college grounds....